Thermostatic socket, holder, or coupling



Feb. 16, 1937. v M. c; DELLINGER 2,071,270.}

THERMQSTATIC SOCKET, HOLDER, OR COUPLING Filed Aug. 9, 1935 Patented Feb. 16, 1937 UNITED STATES THERMOSTATIC SOCKET, HOLDER, OR COUPLING Martin C. Dellingcr. Lancaster, Pa., assignor to K-D Manufacturing Company, Lancaster, Pa., a corporation of Pennsylvania Application August 9, 1935, Serial No. 35,534

8 Claims.

This invention relates to couplings, holders or sockets for use in firmly gripping or holding a part or parts in a heated atmosphere or at a point or place subject to relatively high heat or in the presence of, or in a zone of, high heat and is primarily intended for use in connection with the carbons of motion picture projection machines, spot-lights and for similar purposes, though capable of, and intended for, use wherin ever it is desired'to frictionally grip or couple a part or parts in a zone or atmosphere of high heat.

Heretofore in the motion picture projection art it has been usual to grip the distant ends of the carbon electrodes in such manner as to hold them firmly against vibration and to provide a feed means for progressively moving said electrodes toward each other in accordance with the rate at which their adjacent ends are burned off by the arc, limiting means being interposed in the feed for stopping such feed movement at a given point to prevent injury to the clamping means and primarily to keep the clamping means at all times at such a distance from the zone of intense heat of the are as will avoid such ex- Such limiting means, while usually operative successfully to prevent such loosening of the grip with consequent vibration and resultant flickering, usually stop the clamping means when the carbon electrodes have been burned down to short pieces or pencils roughly about 3 to 4. inches in length. Having this in mind Where a long picture is to be projected and where one or both of the carbon electrodes have been burned down to within an inch or two of the extreme short limit, the careful operator will remove these short used electrodes and replace them with new long carbon electrodes, with the result that an appreciable portion of each such carbon electrode, varying in length from roughly three to six or seven inches cannot be used and becomes Waste.

The present invention has been developed with the above considerations primarily in view and has for its primary object the provision of a thermostatic clamp or socket which will not be adversely effected by heat below the melting point of the metal of which the clamp or socket is constructed; to provide a clamp or socket which may be fed to within half an inch or slightly less of the immediate arc zone or field without being injured; to provide a double ended I socket whereby the heretofore discarded waste short ends may be coupled end to end and used 'down to a short roughly about an inch waste end portion, one said waste piece being clamped by 5' the usual socket and employed simply as a dummy, filler or support and having the thermostatic clamp applied to its otherwise free end, and the other said waste piece having its butt end received and firmly frictionally gripped in the '10 other end of said thermostatic clamp; and to provide a simple, efilcient, durable and inexpensive thermostatic coupling, socket or clamp for the purpose stated.

In the accompanying drawing:

Figure 1 represents a vertical sectional view through a conventional type of motion picture projector showing my invention in side elevation coupling waste carbon lengths for use as electrodes therein; 2

Figure 2, a central longitudinal sectional view through a coupling embodying the preferred form of my invention, with two carbon electrode lengths shown in side elevation coupled thereby;

Figure 3, a view similar to Fig. 2, but prior to :2 the insertion of the carbon electrode length H in the coupling;

Figure 4, a sectional view on the line 4-4 of Figure 2, looking in the direction of the arrows;

Figure 5, a sectional view on the line 55 of 30 Figure 2, looking in the direction of the arrows;

Figure 6, a view similar to Fig. 4 of a slightly modified form;

Figure '7, a view similar to Fig. 4 of a modified split ring form; 35

Figure 3, a view similar to Fig. 4 of a further modification Figure 9, a view similar to Fig. 4 of a further modification; and

Figure 10, a detail perspective exploded view 40 of the preferred form.

Referring now in detail to the accompanying drawing, A designates a projector casing, B, a feed-screw supporting bracket slidably mounted on two spaced supporting and guiding rods C and 5 provided with a handle D extending through the wall of the casing A and by which said bracket B may be moved lengthwise of the rods 0 to the desired position. E designates the reversely threaded feed screw extending through a slot 50 (not shown) in the bottom wall of the casing A, said slot extending lengthwise of the rods C to permit swinging movement of the feed screw E with respect to said casing A and rods 0 as the bracket B is moved lengthwise of said rods C. v55

Two stop collars B are secured to said screw E in spaced relation to each other at the adjacent ends of the reversely threaded portions of said screw E and receive between them the bored upper end b of the bracket B, which upper end constitutes a supporting hub or bearing for the feed screw E freely rotatably received therein, the stop collars B secured to the screw E in any suitable manner as by the pins or set screws indicated preventing endwise movement of said screw E in either direction relative to said hub vl7. During the operation of the projector the screw E will be rotated in the proper direction and at the proper speed by any suitable known means or method, for instance by a drive means such as shown in the patent to Palmer, No. 1,662,434, granted March 13, 1928.

Internally screw-threaded hubs G respectively having screw-thread engagement with the respective reversely threaded screw-thread portions of the operating screw E are adapted to be moved toward and from each other by the rotation of the screw E in the proper directions or corresponding directions of rotation and are prevented from approaching each other beyond a certain point as by the hubs G respectively en gaging the collars B, or by any other suitable mechanical or electrical or electro-mechanical means. The hubs G respectively carry conventional known clamping means F such as now known and used in the art to firmly grip and hold the usual electrodes, in the present instance being employed to grip and hold the dummy, filler or support lengths or pieces H.

The subject matter of the two immediately foregoing paragraphs, including not only the construction of the elements mentioned, but also their association and operation are known, for instance being shown in said Palmer Patent No. 1,662,434, form no part of my invention and may equally well be substituted by any other known form or type of projecting machine operating in any known way, but have been thus briefly described simply to establish a background for my invention and make clear the conditions it must meet in service in order to promote a better understanding of my invention.

In its preferred form, as shown in Figures 1, 2, 3, 4 and 10 my invention consists of a disc-form preferably soft-iron relatively thick block 2 to which two gripping members I are held with slight play in a radial direction by means of a rivet pin 6 passing through holes 3 in the members I and the registering hole 4 in the interposed spacing anchor block 2. Said members I are arcuate in cross-section and disposed diametrically opposite each other with their concave faces opposed to each other and extend equidistantly in opposite directions from said rivet 6, which has its ends upset or riveted over against the outer or convex faces of said members I to hold them in proper assembled relation. The arcs of the crosssectional profiles of the inner faces of said members I will preferably be struck on a circle very slightly larger than the diameter of disc block 2 and preferably substantially the same as the diameter of the carbon electrode pieces H and H to be coupled by the invention, all as clearly shown in Figures 2 to 5 inclusive.

Each said member I is stifily slightly resilient and, prior to the insertion of the carbon pieces H and H, is preferably very slightly, practically infinitesimally, bowed longitudinally, its radially outermost point coinciding with the axis of the rivet 6, the disc block 2 being of such diameter and the rivet 6 being of such length for a given size or diameter of carbon electrode pieces H and H that the members i may rock very slightly relatively to the block 2 prior to the insertion of one or both of said pieces H and H therein, as illustrated in Figure 3. In the embodiments illustrated if but the one piece H or H be inserted in the coupling the members I will not grasp it tightly and it may drop out. If both pieces H and H be inserted the members I will be put under slight compression in a radially outward direction and will assume a practically straight form in longitudinal central section and will tightly and very firmly and securely frictionally grip between their opposed faces the inserted end portions of the pieces H and H engaging the respective outer iaces thereof by substantially the full area of the opposed inner faces of those portions of the members I extending in opposite directions from the end faces of the block 2. However, while such full or large area contact or engagement is preferred both to obtain the fullest and best electrical contact and to obtain the firmest frictional grip and mechanical support, it is not essential and a firm grip with merely such area of contact or engagement as will meet this need and also establish a proper electrical contact will sumce.

Each member I is a bimetallic structure, being formed of such compo-site laminated metal as is commonly used in metal thermostats or commonly and loosely referred to as thermostat metal, the laminae being bonded together in a practically integral composite sheet or structure in accordance with known common practices regularly employed in the production of sheets of such bimetallic metal.

The radially inner sheet, layer or lamina 2' must be of some material, for instance invar steel, having a smaller coefficient of expansion than the outer sheet, layer or lamina 0 which must have a greater coefiicient of expansion than the inner lamina i and which may be of any suitable metal or metal alloy. By having the outer lamina o of a metal or metal alloy having a greater coefficient of expansion than the inner lamina i as the members i are subjected to heat in increasing degree the outer laminae 0 will increase in length more than the inner laminae i, progressively increasing arching or bowing each member l lengthwise thereof in accordance with the increase of the degree of heat, thus forcing the end portions of the members I radially inward against the opposing face portions of the interposed end portions of the carbon electrode pieces H and H and forcing or bulging the medial portions of the members I radially outward tightly against the radially inner faces of the heads or upset ends of the rivet 6, so that the greater the heat, short of the point of softening, melting, fusion or destruction of the members I, the tighter they will grip and hold the pieces H and H.

Thus, initially the stifi resiliency of the members I under normal atmospheric conditions is relied upon to firmly and securely grip and hold the pieces H and H, and as said members I, the block 2 and rivet 4 are subjected to increasingly higher heat the members i are distorted thereby to grip more tightly upon the interposed portions of the pieces H and H instead of being ex panded by the heat to move away from the faces of the interposed pieces H and H and thus release firm grip thereon, any expansion of the block 2 and rivet 4 by the heat being more than compensated for by the distortion of the members I by such heat, with the result that the greater the degree of heat to which the coupling is subjected the greater will be the degree of gripping pressure by the members I of the coupling on the interposed carbon electrode pieces H and H.

Preferably the extreme end portions of the members I will be outwardly rounded or flared as at 5 to facilitate the insertion of the pieces H and H and to avoid abrupt or sharp end edges or corners that might have a tendency to shove or dig into the body of the carbon electrode pieces H and H or to unduly squeeze or compress it in a thin Zone or line across its crosssection with a possible tendency to crack it through or break it off at this point.

While it is preferred that the members I shall be very slightly, almost infinitesimally, bowed lengthwise this is not essential, they may be formed with a very decided bow or arch lengthwise or, on the other hand, may be made perfectly straight or even sli htly dished lengthwise. If made perfectly straight they must be made very closely to a give-n size for a given size of carbon electrode with rather exacting accuracy in order to obtain a firm secure and reliable frictional grip on the pieces H and II under normal atmospheric conditions, whereas if either slightly dished or bowed the stimy resilient character of the members I would permit them tocompensate within themselves for minor inaccuracies and to firmly securely frictionally grip said pieces, this being a very desirable advantage where it is intended to produce the device on a large quantity production basis as a relatively inexpensive article of commerce and not as a scientific precision instrument.

Preferably the block Eand the rivet 6 will be of soft iron, but this is not essential, the block 2 may be of soft iron, the rivet it of any quality of steel or of invar steel, or both the block 2 and rivet 6 may be of any quality of steel or of invar steel or of any other metal found suitable to the purpose, or the block 2 may be of any quality of steel or invar steel and the rivet of soft iron, or the block 2 may be of any material whatsoever suitable to the purpose and the rivet 6 may be of the same or any other material found suitable to the purpose.

The particular metal or metal alloys employed for the individual lamina of the bimetallic members I, and also the manner or method of their association or bonding together into an operatively integral composite laminated structure or sheet form no part of my invention and I am in no way concerned therewith herein, such bimetallic sheet metal being long well known, produced from a number of different known metals and alloys of metals, and bonded, associated or laminated together according to various known methods and processes and is commercially available in the United States in different weights and qualities to suit various conditions of use and it therefore sufiices to select from such commercially available bimetallic material a grade or quality thereof that will withstand the intense heat to which it will be normally subjected in the use intended, which will act as an electric conductor, and which will preferably be stiiily resilient.

In the modification shown in Figure 6 the construction and operation are the same as shown and described with relation to the preferred form, except that the spacing block 2 is made with flattened sides instead of being substantially of disc or circular form.

In the modification shown in Figure '7 the construction and operation are the same as in the preferred form except that the spacing block 20 is a thick stifily resilient, preferably steel, split ring, the resiliency of which may be used to supplement, or in substitution for, the resiliency of the members I in frictionally gripping the pieces H and H under normal atmospheric conditions. Also in this modification two individual or independent rivets are used to respectively secure the respective members I to the block 20 instead of the single rivet 6 of the preferred form.

In the modification illustrated in Figure 8 the 2 is eliminated and instead an embracing binding thick ring 2000, which may be of soft iron or of resilient 'steel or other suitable material, is employed, said ring 2000 being of thick heavy construction extending about, and radially outside of, the members I which are secured thereto at diametrically opposite points by the rivets which in this instance merely serve to hold or maintain the members I in proper lengthwise relationship to the ring 2000 which serves to confine the members I and prevent any relative radially outward movement of the medial portions of said members I after said medial portions have engaged the radially inner face portions of said ring 2000, which, therefore, bears such thrust or strain as may be exerted by said members I when gripping the interposed end portions of the carbon electrode pieces H and H and subjected to the influence of heat.

While the double ended socket or clamp type illustrated is preferred and is especially suited to the primary field of use contemplated, such don-- ble ended socket construction is not essential. to my invention considered in its broader aspects and my invention may be embodied in a single socket clamp, the members I in such case extending only from one end face of the block 2, 2, 20, 200 or 2000 as the case may be, being firmly rigidly secured to the said block as by a rivet or rivets 6 or 60 such as shown by or such length and so tightly headed over as to prevent relative movement between said members I and said block at such point of connection, or by a plurality of such rivets, or by welding, or by any other suitable known means or method, and the bodies of the members I being more pronouncedly endwi'se arched or bowed so as to approach each other slightly more than illustrated so as to firmly and securely frictionally grip the end portion of a piece H or H shoved between, and spreading apart the free end portions of, the members I, and in such case the piece H or H might be any article or thing desired to be held in the presence of heat or where the clamp or socket is subject in its contemplated use to such degree of heat as would be apt to expand, and

release the grip of, the ordinary socket or clamp F that otherwise might be used, and therefore the invention is not to be regarded as restricted in use to holding or coupling carbon or other electrodes but may be advantageously used in any art under any conditions where it is desired that the socket, holder or clamp will not be released by expansion under the influence of heat to release, or permit the wobbling or vibration of, the article held.

I claim:

1. A thermostatic socket comprising a pair of opposed spaced longitudinally arched stifliy res lient gripping members, in combination with a disc-form spacing metal block interposed between the medial portions of said members, and a rivet passing through registering holes in said members and said block and having its ends upset to respectively overlie and engage the radially outer faces of said members to permanently secure said members and block together in operative relation with a limited amount of play, said members respectively having their respective extreme outer end portions radially outwardly flared to avoid an abrupt edge, and each said member being formed of bimetal and being arcuate in transverse cross-section, the outer lamina of each said member having a greater coefiicient of expansion than the inner lamina of said member, the arc of the inner face of said transverse cross-section being struck on a circle of greater diameter than the diameter of said block to facilitate limited play between said block and each of said members, and the extreme radially outer portion of the longitudinal arch of each said member being substantially coincident with the axis of said rivet.

2. A thermostatic socket comprising a pair of spaced opposed longitudinally arched gripping members, in combination with a spacing block interposed between the medial portions of said members, and means securing said members to said block, each said member being formed of bimetal and being arcuate in transverse crosssection, the outer lamina of each said member having a greater coefficient of expansion than the inner lamina of said member.

3. A thermostatic socket comprising a pair of opposed spaced longitudinally extending gripping members, in combination with a spacing block interposed between the medial portions of said members, said members being riveted to said block, each said member being formed of bimetal and being arched in longitudinal section,

the outer lamina of each said member having a greater coeificient of expansion than the inner lamina of said member, and the extreme radially outer portion of the longitudinal arch of each said member lying in a transverse plane intersecting said block.

4. A thermostatic socket comprising a pair of opposed spaced longitudinally extending gripping members, in combination with a spacing block interposed between the medial portions of said members, and means permanently connecting said members to said block, each said member being formed of bimetal, the outer lamina of each said member having a greater coefiicient of expansion than the inner lamina of said member.

5. A thermostatic socket comprising a pair of opposed longitudinally extending gripping members, in combination with means extending about said members between their ends and limiting their bodily movement in opposite directions away from each other, each said member being formed of bimetal, and the outer lamina of each said member having a greater coefiicient of expansion than the inner lamina of said member.

6. A thermostatic socket comprising two opposed stifl'iy resilient bimetallic members and means engaging the medial portions of said members and limiting the movement of said portions away from each other, the outer lamina of each said member having a greater coefiicient of expansion than the inner lamina of said member.

'7. A thermostatic socket comprising two opposed bimetallic members and means preventing bodily movement of said members away from each other, the outer lamina of each said mern- 

